Occlusal Plane Stability After Curvilinear Mandibular Distraction Osteogenesis

Area of Science:

• Craniofacial surgery
• Orthodontics
• Pediatric dentistry

Background:

• Mandibular hypoplasia often requires surgical intervention for correction.
• Curvilinear mandibular distraction osteogenesis (MDO) offers simultaneous sagittal and vertical mandibular lengthening.
• Long-term stability of occlusal plane changes after MDO in mixed dentition is not well-established.

Purpose of the Study:

• To evaluate the stability of occlusal plane changes following curvilinear MDO in pediatric patients with mixed dentition.
• To assess cephalometric changes in Sella-nasion-B point angle (SNB), SN-mandibular plane angle (MPA), and SN-occlusal plane angle (OPA).
• To compare outcomes between patients with and without postoperative orthodontic treatment.

Main Methods:

• Retrospective review of 25 patients undergoing curvilinear MDO (2009-2024).
• Cephalometric analysis of preoperative, immediate postoperative, and extended postoperative imaging (mean follow-up: 4 years).
• Assessment of SNB, MPA, and OPA angles; comparison of outcomes with and without orthodontics.

Main Results:

• Significant improvements in SNB (69° to 76°), MPA (57° to 48°), and OPA (30° to 23°) were observed post-MDO (P<0.001).
• These cephalometric improvements remained relatively stable at the 4-year follow-up.
• Occlusal plane angle relapse was similar between patients with and without postoperative orthodontics (P>0.05).
• 50% of tracheostomy-dependent patients were decannulated postoperatively.

Conclusions:

• Curvilinear MDO provides significant and relatively stable cephalometric improvements in patients with mixed dentition.
• The procedure positively impacts mandibular skeletal and occlusal plane morphology.
• Further long-term studies are warranted to fully understand the risk/benefit ratio of curvilinear MDO.